Purification and characterization of glucose oxidase from ligninolytic cultures of Phanerochaete chrysosporium

Glucose oxidase, an important source of hydrogen peroxide in lignin-degrading cultures of Phanerochaete chrysosporium, was purified to electrophoretic homogeneity by a combination of ion-exchange and molecular sieve chromatography. The enzyme is a flavoprotein with an apparent native molecular weight of 180,000 and a denatured molecular weight of 80,000. This enzyme does not appear to be a glycoprotein. It gives optimal activity with D-glucose, which is stoichiometrically oxidized to D-gluconate. The enzyme has a relatively broad pH optimum of 4 to 5. It is inhibited by Ag+ (10 mM) and o-phthalate (100 mM), but not by Cu2+, NaF, or KCN (each 10 mM).